Introduction
If you have been involved in even a moderately sized Visual Basic project,
then you undoubtably have run into issues associated with maintaining compatibility
between different versions of your ActiveX components. While it seems like this
should be a simple concept, the details require an understanding of some of the
'guts' of COM object plumbing. Not for the faint of heart. In this article, we
discuss these details and walk you through the process of determining what compatibility
setting is best suited for your project.
As a starting point, compatibility is only an issue if you're creating an ActiveX
DLL. If all of your classes fit inside one single executable, then compatibility
will not come into play. Once you have created your new project, select Project
| Project Properties and select the Component tab. At the bottom of the dialog
box, you can select from No Compatibility, Project Compatibility and Binary Compatibility.
If you specify Binary Compatibility, you must also provide the path to an existing
component to act as the base for the interface. But more on that later.